Cytosolic phosphoglycerate mutase dimers (PGAM1,2) catalyze the reversible isomerisation of 2- and 3-phosphoglycerate (2PG; 3PG). There are two isoforms of this enzyme, PGAM1 (isoform B) and PGAM2 (isoform M). In the body, erythrocytes express only PGAM1, while skeletal muscle expresses only PGAM2. Other tissues express both isoforms (Omenn & Cheung 1974; Repiso et al. 2005; Tsujino et al. 1993).